1. Technical Field
The present disclosure relates generally to a storage device, and more particularly to an improved memory connection structure in a storage device.
2. Description of Related Art
In general, a storage device is composed of volatile memories which are connected in series on the same bits. As a result, when the storage device accesses data, a problem of signal reflection would easily occur.
Reference is made to FIG. 1 and FIG. 2 which are an architecture view of a related art. first memory and an architecture view of a related art second memory, respectively. The storage device mainly includes a control chip 11, a bus 12, and a plurality of volatile memories 13. The control chip 11 is connected to the volatile memories 13 via the bus 12. As shown in FIG. 1, when the control chip 11 accesses only one of the volatile memories 13, micro currents 21 would flow to other non-accessed volatile memories 13. hi addition, when the length of the bus is longer, namely the amount of the in-series volatile memories 13 on the bus 12 is more and the currents flowing to the volatile memories 13 are higher.
Because the non-accessed volatile memories 13 are not driven by the currents, the currents would reflect to the control chip 11 to form reflected currents 22 as shown in FIG. 2, thus generating the phenomenon of signal flection. As mentioned above, once the amount of the in-series volatile memories 13 on the bus 12 is more, the reflected currents 22 are higher. However, the reflected currents 22 would interfere with and even mistake the original access signals and data.
In order to overcome the problem of signal reflection, the technology of on-die termination (ODT) is introduced. In general, the volatile memory 13 must have the built-in ODT pin; the control chip 11 can implement the ODT function of the volatile memory 13 via the ODT pin, such as the DDR3. The ODT function is executed so that a specific value resistor is simulated in the volatile memory 13. Accordingly, when the volatile memory 13 receives the micro currents 21, the received micro current 21 could be guided to the resistor, but would not form the reflected currents 22.
When the ODT function of the volatile memory 13 is executed, however, the overall power consumption of the storage device would be increased, thus causing its temperature to increase. In experiments performed by the applicants, when the volatile memory 13 is continuously accessed for 30 minutes at 23-degree room temperature without executing the ODT function, the average temperature of the volatile memory 13 is 33 degrees Celsius. In particular, the average consumption current and power of accessing the volatile memory 13 are 1.1 amperes and 1.65 watts, respectively. Also, the average consumption current and power of writing the volatile memory 13 are 1.2 amperes and 1.8 watts, respectively. On the contrary, when the volatile memory 13 is operated with executing the ODT function, the average temperature of the volatile memory 13 is 37.9 degrees Celsius. In particular, the average consumption current and power of accessing the volatile memory 13 are 1.2 amperes and 1.8 watts, respectively. Also, the average consumption current and power of writing the volatile memory 13 are 2.8 amperes and 4.2 watts, respectively.
As mentioned above, although the ODT function can be used to overcome the problem of signal reflection, the caused higher temperature, consumption current, and consumption power and are inevitable. For this reason, it is very significant for technicians to research and develop solutions to overcome the problem of the signal reflection without using the ODT technology.